1. Field of the Invention
The present invention relates to a tape carrier for TAB (hereinafter referred to as “TAB tape carrier”) and a method for producing the same and particularly to a TAB tape carrier for mounting electronic parts by a TAB method and a method for producing the same.
2. Related Art
A TAB tape carrier is widely used for mounting electronic parts such as semiconductor devices by a TAB (Tape Automated Bonding) method. Generally, in the TAB tape carrier, a plurality of wiring circuits for mounting electronic parts are provided at regular intervals.
The wiring circuits may contain defective products having electrical failure or visual failure. In such a case, electronic parts are mounted while defective products are avoided at the time of mounting electronic parts. The yield on continuous production is however lowered when electronic parts are mounted while defective products are avoided.
On the other hand, for example, a method applied to an MTCP (multi-chip TCP formed in such a manner that a plurality of semiconductor chips each having a built-in memory are electrically connected (linked) while mechanically connected as a horizontal row to a tape carrier of a TCP (Tape Carrier Package)) has been described in Japanese Patent Laid-Open No. 2002-76068A. In the method, the plurality of semiconductor chips mechanically and electrically connected to the tape carrier are inspected in an inspection step. When any semiconductor chip as a defective product having electrical failure or visual failure is found, the semiconductor chip as a defective product is punched together with a portion of the tape carrier where the semiconductor chip as a defective product is connected. A non-defective piece, which is formed in such a manner that a semiconductor chip non-defective in terms of electricity and external appearance is connected to a tape carrier and which is similar in shape to and slightly larger in size than the punched portion, is mechanically and electrically connected to the punched portion by soldering. In this manner, lowering of the yield in production is prevented.
The aforementioned method is however to be applied to an MTCP. In the MTCP, it is necessary to punch the defective semiconductor chip along with the tape carrier because all semiconductor chips including the defective one are mechanically and electrically connected to the tape carrier. It is therefore necessary to replace the punched portion with a non-defective semiconductor chip along with a tape carrier similar in shape to but slightly larger in size than the punched portion and solder the non-defective semiconductor chip to connect the non-defective semiconductor chip mechanically and electrically.
When a non-defective individual piece of tape carrier larger than the punched portion is soldered to the punched portion in this manner, the non-defective individual piece of tape carrier is piled on the punched portion of the tape carrier so that a difference in level is formed in the overlapping portion.
On the other hand, when a defective product in the plurality of wiring circuits provided in the TAB tape carrier is to be replaced by the same method as described above, a wiring circuit judged as a defective product is first punched out along with part of the tape carrier on which the defective wiring circuit is disposed. Then, a non-defective wiring circuit is provided on the punched portion so that a tape carrier similar in shape to but slightly larger in size than the punched portion is laminated on the punched portion. Also in this case, a difference in level is still formed in the overlapping portion.
In the TAB tape carrier, electronic parts are however mounted on wiring circuits respectively, for example, by solder joint after that. Accordingly, at the time of mounting such electronic parts, the difference in level unfavorably causes lowering of reliability of connection between the electronic parts and the wiring circuits.
In addition, in the aforementioned method, in the case where a defective semiconductor chip is found by inspection in an inspection step after semiconductor chips are mounted on a tape carrier, part of the tape carrier is punched out along with the defective semiconductor chip and then a non-defective individual piece is soldered. Accordingly, the labor required for punching and soldering is troublesome, and production cost increases inevitably.